1. Field of the Invention
The present invention relates to a dicing machine which dices a work or semiconductor wafer.
2. Description of the Related Art
The dicing machine is an apparatus in which a rotary blade rotates at a high speed and dices a work or a semiconductor wafer. Parts of the blade except a cutting part are covered with a flange cover. The flange cover is provided with a pair of nozzles, through which cutting solution is jetted to both sides of the blade cutting the work.
The flange cover is divided into two to facilitate replacement of the blade. The conventional flange cover is divided into two at a boundary plane perpendicular to a rotary shaft of the blade. In the two covers, a first cover which is positioned to the motor side is fixed to a stationary member such as the motor, and a second cover is connected to the first cover with bolts. Each of the first and second covers is provided with one of the nozzles. If the flange cover is an integrated unit, the nozzles obstruct the replacement of the blade. Hence, when the blade is replaced, the second cover is removed from the first cover so as to remove the nozzle.
The flange cover is also provided with a breakage detector, which optically detects breakage of the blade without contacting the blade. The breakage detector comprises a light-projecting unit including a light and its optical system, and a light-receiving unit including a light-receiving device and its optical system. The light-projecting unit and the light-receiving unit are arranged to face each other across the blade. The light-projecting unit is attached to the first cover, and the light-receiving unit is attached to the second cover. Since the light-receiving unit also obstructs the replacement of the blade, the second cover is removed so as to remove the light-receiving unit.
In this conventional dicing machine, the second cover must be removed from the first cover whenever the blade is replaced, therefore much time is needed for the replacement of the blade.
In order to solve the above-described problem, Japanese Patent Application Publication No. 11-251263 discloses a dicing machine that has a partially-turnable flange cover 36 shown in FIG. 6. The flange cover 36 is divided into the first cover 38 and the second cover 40. The second cover 40 can turn within a plane perpendicular to a rotary shaft 18A of the rotary blade 18 with respect to the first cover 38. The second cover 40 is provided with a pair of coolant jetting nozzles 20 and a breakage detector 50, which includes the light-projecting unit and the light-receiving unit as an integrated unit. When the rotary blade 18 is replaced, the operator has only to turn the second cover 40 so as to withdraw the second cover 40, the coolant jetting nozzles 20 and the breakage detector 50 from the rotary blade 18, without removing the second cover 40.
However, the operator still has to manually turn the second cover 40, and it is a problem to introduce an automatic system for replacing the blade disclosed in Japanese Patent Application Publication No. 11-340169 and so forth.
In the conventional dicing machine, the light-projecting unit and the light-receiving unit of the blade breakage detecting device are arranged on the flange cover near the blade. Hence, there is another problem that the light-projecting face and the light-receiving face are soiled with water containing cutting powders produced on the cutting of the work, and the detectability of the breakage detecting device gradually deteriorates.
The present invention has an object to provide a dicing machine in which the rotary blade can be exchanged easily without needing a lot time, can correspond with the system for exchanging the rotary blades automatically, and further can automatically check a detecting ability of the blade breakage detector.
In order to attain the above described object, the present invention is directed to a dicing machine which processes a work with a rotary blade, the dicing machine comprising: a spindle on which the rotary blade is attached and rotated, the spindle moving in a vertical direction in processing of the work; a turnable cover which covers the rotary blade in processing of the work; an axis on which the turnable cover is turnably arranged, the axis being parallel with the spindle; and a nozzle through which liquid is applied toward the rotary blade in processing of the work, the nozzle being arranged on the turnable cover, wherein the turnable cover is turned in connection with vertical movement of the spindle so that the nozzle is moved away from the rotary blade.
According to the present invention, since the turnable cover turns to follow the vertical movement of the spindle, the nozzles can automatically retreat from the rotary blade.
Preferably, when the spindle moves upward, the turnable cover is turned upward to open; and when the spindle moves downward, the turnable cover is turned downward to close. According to the present invention, the nozzles can automatically retreat from the rotary blade when the spindle moves up, and can automatically return to the original positions when the spindle moves down.
Preferably, the dicing machine further comprises: a breakage detector which detects breakage of the rotary blade, the breakage detector being arranged on the turnable cover, wherein the breakage detector is moved away from the rotary blade when the turnable cover is turned upward to open. According to the present invention, the breakage detector can automatically retreat from the rotary blade when the spindle moves up, and can automatically return to the original position when the spindle moves down.
Preferably, the breakage detector comprises an optical detector including a light-projecting unit and a light-receiving part, and ascertains whether a received luminous energy in the light-receiving part is within a predetermined range when the breakage detector is moved away from the rotary blade. According to the present invention, the breakage detector can automatically determines whether the detectability thereof deteriorates by the contamination on the light-projecting face and the light-receiving face of the light-projecting unit and the light-receiving part.
According to the present invention, the cutting blade can be replaced easily without needing a lot time, and the automatic blade replacing system can be applied. Moreover, the detectability can be checked automatically in the case that the blade breakage detector retreats from the rotary blade.